Experimental study on discharging characteristics of thermal energy storage system with discontinuous fins

Efficient thermal storage technologies are of vital importance for addressing the intermittent supply issue of renewable energy and the problem of industrial waste heat recovery. However, the application efficiency of traditional tubular thermal storage systems is limited due to their low heat release rate. This paper presents an experimental investigation into the influence of discontinuous fins on the temperature field distribution, the evolution of the phase interface, and the temperature response rate during the solidification process. The influence mechanism of the cooling fluid temperature on the heat release characteristics is also discussed. The results show that the periodic contraction-expansion design of discontinuous fins effectively promotes heat transfer and weakens local thermal resistance. Compared with traditional longitudinally straight fins, discontinuous fins reduce the complete solidification time by 26.2 %. They also improve the temperature response rates in both the radial and axial directions, lower the average temperature uniformity index, and effectively increase heat transfer efficiency. Furthermore, when the cooling temperature is reduced from 30 °C to 10 °C, the complete solidification time is shortened by 37.3 %, but the temperature uniformity index increases by 129.8 %. This research provides new ideas and an experimental basis for the optimal design of phase change heat storage devices.